   aggregator (sum, max, etc.).  If lower, each MODIS pixel is tagged with the ASCII
   grid cell that it falls within.  Note that the ASCII grid must be in WGS84, with row
   indices prepended and the ASCII header lopped off."
-  ([m-res dataset tile-seq ascii-path & [agg]]
+  ([m-res dataset pixel-tap ascii-path & [agg]]
      (let [ascii-info ((keyword dataset) datasets)
            grid-source (ascii-source ascii-path)]
        (if (>= (:cellsize ascii-info) 0.01)
-         (low-res-sample dataset ascii-info (mod-pixels tile-seq) grid-source)
+         (low-res-sample dataset m-res ascii-info pixel-tap grid-source)
          (high-res-sample dataset m-res grid-source ascii-info agg)))))
 
 ;; THE JOB!


(defn low-res-sample
  "sample values off of a lower resolution grid than the MODIS grid."
  [dataset ascii-info mod-source grid-source]
  (<- [?dataset ?m-res ?t-res ?mod-h ?mod-v ?sample ?line ?outval]
      (grid-source ?row ?col ?outval)
      (identity dataset :> ?dataset)
      (identity "00" :> ?t-res)
      (mod-source ?m-res ?mod-h ?mod-v ?sample ?line)
      (modis-sample ascii-info ?m-res ?mod-h ?mod-v ?sample ?line :> ?row ?col)))

;; TODO: Right now, we use the 0.1 as an indicator for conversion
;; direction, between modis and wgs84. Replace with a calculation.

  (:use cascalog.api
        [forma.matrix.utils :only (idx->colrow)]
        [forma.hadoop.io :only (chunk-tap)]
        [forma.hadoop.predicate :only (sparse-windower
                                       pixel-generator)]
        [forma.reproject :only (wgs84-index
                                dimensions-at-res
                                modis-sample)]
